1 /*
2 * W83877F Computer Watchdog Timer driver
3 *
4 * Based on acquirewdt.c by Alan Cox,
5 * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * The authors do NOT admit liability nor provide warranty for
13 * any of this software. This material is provided "AS-IS" in
14 * the hope that it may be useful for others.
15 *
16 * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net>
17 *
18 * 4/19 - 2001 [Initial revision]
19 * 9/27 - 2001 Added spinlocking
20 * 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments
21 * Eliminate fop_read
22 * Eliminate extra spin_unlock
23 * Added KERN_* tags to printks
24 * add CONFIG_WATCHDOG_NOWAYOUT support
25 * fix possible wdt_is_open race
26 * changed watchdog_info to correctly reflect what
27 * the driver offers
28 * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
29 * WDIOC_SETTIMEOUT,
30 * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
31 * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces
32 * added extra printk's for startup problems
33 * use module_param
34 * made timeout (the emulated heartbeat) a
35 * module_param
36 * made the keepalive ping an internal subroutine
37 *
38 * This WDT driver is different from most other Linux WDT
39 * drivers in that the driver will ping the watchdog by itself,
40 * because this particular WDT has a very short timeout (1.6
41 * seconds) and it would be insane to count on any userspace
42 * daemon always getting scheduled within that time frame.
43 */
44
45 #include <linux/module.h>
46 #include <linux/moduleparam.h>
47 #include <linux/types.h>
48 #include <linux/timer.h>
49 #include <linux/jiffies.h>
50 #include <linux/miscdevice.h>
51 #include <linux/watchdog.h>
52 #include <linux/fs.h>
53 #include <linux/ioport.h>
54 #include <linux/notifier.h>
55 #include <linux/reboot.h>
56 #include <linux/init.h>
57 #include <linux/io.h>
58 #include <linux/uaccess.h>
59 #include <asm/system.h>
60
61 #define OUR_NAME "w83877f_wdt"
62 #define PFX OUR_NAME ": "
63
64 #define ENABLE_W83877F_PORT 0x3F0
65 #define ENABLE_W83877F 0x87
66 #define DISABLE_W83877F 0xAA
67 #define WDT_PING 0x443
68 #define WDT_REGISTER 0x14
69 #define WDT_ENABLE 0x9C
70 #define WDT_DISABLE 0x8C
71
72 /*
73 * The W83877F seems to be fixed at 1.6s timeout (at least on the
74 * EMACS PC-104 board I'm using). If we reset the watchdog every
75 * ~250ms we should be safe. */
76
77 #define WDT_INTERVAL (HZ/4+1)
78
79 /*
80 * We must not require too good response from the userspace daemon.
81 * Here we require the userspace daemon to send us a heartbeat
82 * char to /dev/watchdog every 30 seconds.
83 */
84
85 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
86 /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
87 static int timeout = WATCHDOG_TIMEOUT;
88 module_param(timeout, int, 0);
89 MODULE_PARM_DESC(timeout,
90 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
91 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
92
93
94 static int nowayout = WATCHDOG_NOWAYOUT;
95 module_param(nowayout, int, 0);
96 MODULE_PARM_DESC(nowayout,
97 "Watchdog cannot be stopped once started (default="
98 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
99
100 static void wdt_timer_ping(unsigned long);
101 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
102 static unsigned long next_heartbeat;
103 static unsigned long wdt_is_open;
104 static char wdt_expect_close;
105 static DEFINE_SPINLOCK(wdt_spinlock);
106
107 /*
108 * Whack the dog
109 */
110
111 static void wdt_timer_ping(unsigned long data)
112 {
113 /* If we got a heartbeat pulse within the WDT_US_INTERVAL
114 * we agree to ping the WDT
115 */
116 if (time_before(jiffies, next_heartbeat)) {
117 /* Ping the WDT */
118 spin_lock(&wdt_spinlock);
119
120 /* Ping the WDT by reading from WDT_PING */
121 inb_p(WDT_PING);
122
123 /* Re-set the timer interval */
124 mod_timer(&timer, jiffies + WDT_INTERVAL);
125
126 spin_unlock(&wdt_spinlock);
127
128 } else
129 printk(KERN_WARNING PFX
130 "Heartbeat lost! Will not ping the watchdog\n");
131 }
132
133 /*
134 * Utility routines
135 */
136
137 static void wdt_change(int writeval)
138 {
139 unsigned long flags;
140 spin_lock_irqsave(&wdt_spinlock, flags);
141
142 /* buy some time */
143 inb_p(WDT_PING);
144
145 /* make W83877F available */
146 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
147 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
148
149 /* enable watchdog */
150 outb_p(WDT_REGISTER, ENABLE_W83877F_PORT);
151 outb_p(writeval, ENABLE_W83877F_PORT+1);
152
153 /* lock the W8387FF away */
154 outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);
155
156 spin_unlock_irqrestore(&wdt_spinlock, flags);
157 }
158
159 static void wdt_startup(void)
160 {
161 next_heartbeat = jiffies + (timeout * HZ);
162
163 /* Start the timer */
164 mod_timer(&timer, jiffies + WDT_INTERVAL);
165
166 wdt_change(WDT_ENABLE);
167
168 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
169 }
170
171 static void wdt_turnoff(void)
172 {
173 /* Stop the timer */
174 del_timer(&timer);
175
176 wdt_change(WDT_DISABLE);
177
178 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
179 }
180
181 static void wdt_keepalive(void)
182 {
183 /* user land ping */
184 next_heartbeat = jiffies + (timeout * HZ);
185 }
186
187 /*
188 * /dev/watchdog handling
189 */
190
191 static ssize_t fop_write(struct file *file, const char __user *buf,
192 size_t count, loff_t *ppos)
193 {
194 /* See if we got the magic character 'V' and reload the timer */
195 if (count) {
196 if (!nowayout) {
197 size_t ofs;
198
199 /* note: just in case someone wrote the magic
200 character five months ago... */
201 wdt_expect_close = 0;
202
203 /* scan to see whether or not we got the
204 magic character */
205 for (ofs = 0; ofs != count; ofs++) {
206 char c;
207 if (get_user(c, buf + ofs))
208 return -EFAULT;
209 if (c == 'V')
210 wdt_expect_close = 42;
211 }
212 }
213
214 /* someone wrote to us, we should restart timer */
215 wdt_keepalive();
216 }
217 return count;
218 }
219
220 static int fop_open(struct inode *inode, struct file *file)
221 {
222 /* Just in case we're already talking to someone... */
223 if (test_and_set_bit(0, &wdt_is_open))
224 return -EBUSY;
225
226 /* Good, fire up the show */
227 wdt_startup();
228 return nonseekable_open(inode, file);
229 }
230
231 static int fop_close(struct inode *inode, struct file *file)
232 {
233 if (wdt_expect_close == 42)
234 wdt_turnoff();
235 else {
236 del_timer(&timer);
237 printk(KERN_CRIT PFX
238 "device file closed unexpectedly. Will not stop the WDT!\n");
239 }
240 clear_bit(0, &wdt_is_open);
241 wdt_expect_close = 0;
242 return 0;
243 }
244
245 static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
246 {
247 void __user *argp = (void __user *)arg;
248 int __user *p = argp;
249 static const struct watchdog_info ident = {
250 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
251 | WDIOF_MAGICCLOSE,
252 .firmware_version = 1,
253 .identity = "W83877F",
254 };
255
256 switch (cmd) {
257 case WDIOC_GETSUPPORT:
258 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
259 case WDIOC_GETSTATUS:
260 case WDIOC_GETBOOTSTATUS:
261 return put_user(0, p);
262 case WDIOC_SETOPTIONS:
263 {
264 int new_options, retval = -EINVAL;
265
266 if (get_user(new_options, p))
267 return -EFAULT;
268
269 if (new_options & WDIOS_DISABLECARD) {
270 wdt_turnoff();
271 retval = 0;
272 }
273
274 if (new_options & WDIOS_ENABLECARD) {
275 wdt_startup();
276 retval = 0;
277 }
278
279 return retval;
280 }
281 case WDIOC_KEEPALIVE:
282 wdt_keepalive();
283 return 0;
284 case WDIOC_SETTIMEOUT:
285 {
286 int new_timeout;
287
288 if (get_user(new_timeout, p))
289 return -EFAULT;
290
291 /* arbitrary upper limit */
292 if (new_timeout < 1 || new_timeout > 3600)
293 return -EINVAL;
294
295 timeout = new_timeout;
296 wdt_keepalive();
297 /* Fall through */
298 }
299 case WDIOC_GETTIMEOUT:
300 return put_user(timeout, p);
301 default:
302 return -ENOTTY;
303 }
304 }
305
306 static const struct file_operations wdt_fops = {
307 .owner = THIS_MODULE,
308 .llseek = no_llseek,
309 .write = fop_write,
310 .open = fop_open,
311 .release = fop_close,
312 .unlocked_ioctl = fop_ioctl,
313 };
314
315 static struct miscdevice wdt_miscdev = {
316 .minor = WATCHDOG_MINOR,
317 .name = "watchdog",
318 .fops = &wdt_fops,
319 };
320
321 /*
322 * Notifier for system down
323 */
324
325 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
326 void *unused)
327 {
328 if (code == SYS_DOWN || code == SYS_HALT)
329 wdt_turnoff();
330 return NOTIFY_DONE;
331 }
332
333 /*
334 * The WDT needs to learn about soft shutdowns in order to
335 * turn the timebomb registers off.
336 */
337
338 static struct notifier_block wdt_notifier = {
339 .notifier_call = wdt_notify_sys,
340 };
341
342 static void __exit w83877f_wdt_unload(void)
343 {
344 wdt_turnoff();
345
346 /* Deregister */
347 misc_deregister(&wdt_miscdev);
348
349 unregister_reboot_notifier(&wdt_notifier);
350 release_region(WDT_PING, 1);
351 release_region(ENABLE_W83877F_PORT, 2);
352 }
353
354 static int __init w83877f_wdt_init(void)
355 {
356 int rc = -EBUSY;
357
358 if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */
359 timeout = WATCHDOG_TIMEOUT;
360 printk(KERN_INFO PFX
361 "timeout value must be 1 <= x <= 3600, using %d\n",
362 timeout);
363 }
364
365 if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) {
366 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
367 ENABLE_W83877F_PORT);
368 rc = -EIO;
369 goto err_out;
370 }
371
372 if (!request_region(WDT_PING, 1, "W8387FF WDT")) {
373 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
374 WDT_PING);
375 rc = -EIO;
376 goto err_out_region1;
377 }
378
379 rc = register_reboot_notifier(&wdt_notifier);
380 if (rc) {
381 printk(KERN_ERR PFX
382 "cannot register reboot notifier (err=%d)\n", rc);
383 goto err_out_region2;
384 }
385
386 rc = misc_register(&wdt_miscdev);
387 if (rc) {
388 printk(KERN_ERR PFX
389 "cannot register miscdev on minor=%d (err=%d)\n",
390 wdt_miscdev.minor, rc);
391 goto err_out_reboot;
392 }
393
394 printk(KERN_INFO PFX
395 "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
396 timeout, nowayout);
397
398 return 0;
399
400 err_out_reboot:
401 unregister_reboot_notifier(&wdt_notifier);
402 err_out_region2:
403 release_region(WDT_PING, 1);
404 err_out_region1:
405 release_region(ENABLE_W83877F_PORT, 2);
406 err_out:
407 return rc;
408 }
409
410 module_init(w83877f_wdt_init);
411 module_exit(w83877f_wdt_unload);
412
413 MODULE_AUTHOR("Scott and Bill Jennings");
414 MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
415 MODULE_LICENSE("GPL");
416 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
417
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